Multiple wavelength X-ray dispersive devices and method of making the devices

Abstract

Multiple wavelength X-ray dispersive devices and method of forming them are provided which reflect at least two wavelengths of interest at the same or different angles. The devices include a plurality of layer sets formed on one another, each set having at least two units. At least one unit includes at least two layers having a first d spacing and the second unit has at least one layer with a second d spacing. A plurality of one or both of the units can also be provided in each layer set.

What is claimed and desired to be secured by Letters Patent of the United States is: 
     
       1. A multiple wavelength x-ray diffraction device comprising: a plurality of layer sets formed on one another, each of said layer sets including at least a first unit, U 1 , and a second interleaved unit, U 2  ;   said first unit U 1  including at least two layers, said first unit having a first interplanar spacing, d 1 , causing said layer sets to have x-ray diffraction properties at a first wavelength of interest λ 1  ;   said second unit, U 2  including at least two layers, said second unit having a second interplanar spacing d 2 , different from d 1  causing said layer sets to have x-ray diffraction properties at a second wavelength of interest(.) λ 2  different from d 1 , and;   said layer sets including a first unit, U 1 , and a second unit, U 2 , to form a structure of alternating U 1  and U 2  units and having an interplanar spacing (d 1  +d 2 ).   
     
     
       2. The device as defined in claim 1 wherein each of said first and second units is formed at least from alternating layers of two materials, said two materials being the same for each of said first and second units. 
     
     
       3. The device as defined in claim 1 wherein each of said first and second units are formed at least from alternating layers of two materials, said two materials being different for said first and said second units. 
     
     
       4. The device as defined in claim 1 wherein each of said layer sets includes more than one of said first or said second units. 
     
     
       5. The device as defined in claim 4 wherein each of said layer sets includes more than one of said first and said second units. 
     
     
       6. The device as defined in claim 1 wherein each of said layer sets includes at least a third unit, said third unit including at least two layers, said third unit having a third interplanar spacing, d 3 , causing said layer sets to have x-ray diffraction properties at a third wavelength of interest λ 3 . 
     
     
       7. The device as defined in claim 1 wherein said layer sets are designed such that said first and second wavelengths, λ 1 , and λ 2 , of interest are diffracted at the same angle. 
     
     
       8. The device as defined in claim 1 wherein said layer sets are designed such that said first and second wavelengths of interest, λ 1  and λ 2  are at different angles. 
     
     
       9. A method of forming a multiple wavelength x-ray diffraction device, comprising: forming a plurality of layer sets on one another, each of said layer sets including at least a first unit U 1 , and a second unit U 2  ;   forming said first unit U 1  including at least two layers having a first interplanar spacing d 1  causing said layer sets to have x-ray diffraction properties at a first wavelength of interest λ 1  ; and λ.sub.   forming said second unit including at least two layers having a second interplanar spacing, d 2  different from d 1 , causing said layer sets to have x-ray diffraction properties substantially at a second wavelength of interest different from λ 1 .   
     
     
       10. The method as defined in claim 9 including forming said first unit U 1  and second Units U 2  from at least alternating layers of two materials, said two materials being the same for each of said first and second units. 
     
     
       11. The method as defined in claim 9 including forming each of said first and second units from at least alternative layers of two materials, said two materials being different for said first and said second units. 
     
     
       12. The method as defined in claim 9 including forming each of said layer sets with more than one of said first or said second units. 
     
     
       13. The method as defined in claim 12 including forming each of said layer sets from more than one of said first and said second units. 
     
     
       14. The method as defined in claim 9 including forming each of said layer sets with at least a third unit U 3  including at least two layers and forming said third unit with a third interplanar spacing d 3  different from d 1  and d 2  causing said layer sets to have x-ray diffraction properties at a third wavelength of interest λ 3 . 
     
     
       15. The method as defined in claim 9 including forming said layer sets such that said first and second wavelengths of interest are diffracted at the same angle. 
     
     
       16. The method as defined in claim 9 including forming said layer sets such that said first and second wavelengths of interest are diffracted at different angles.